18993388 has 24 divisors (see below), whose sum is σ = 35421120. Its totient is φ = 8885520.

The previous prime is 18993371. The next prime is 18993391. The reversal of 18993388 is 88339981.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4803 + ... + 7813.

It is an arithmetic number, because the mean of its divisors is an integer number (1475880).

Almost surely, 2^18993388 is an apocalyptic number.

It is an amenable number.

18993388 is a deficient number, since it is larger than the sum of its proper divisors (16427732).

18993388 is a wasteful number, since it uses less digits than its factorization.

18993388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3117 (or 3115 counting only the distinct ones).

The product of its digits is 373248, while the sum is 49.

The square root of 18993388 is about 4358.1404291280. The cubic root of 18993388 is about 266.8092078218.

The spelling of 18993388 in words is "eighteen million, nine hundred ninety-three thousand, three hundred eighty-eight".